Web App for Cocoa Purchasing

Looking for an experienced front and backend developer. Must be experienced with the platform that works best. We are creating a fully Automated and Rich Internet Application, with the best UI for Purchasing Cocoa. We want auto calibration with the scale through a Bluetooth scale which will automatically calculate the amount to paid to the farmer based on the weight and the application will automatically pay the farmer either by Mobile Money or bank transfer. This means the Farmers, Purchasing Officers, Supervisors, Accountants, Senior Accountants, Managers, and Directors will be able to create and have their own individual accounts and special privileges assigned by the Senior Administrator. In simple terms, our purchasing officers goes to buy from the farmer by weighing the Cocoa using a Bluetooth compatible scale which will send the information to the application which will then calculate how much is needed to be paid to the farmer and the application automatically pays the farmer with a single click from the purchasing officer. The purchasing officer will send all purchased items to a warehouse. Here the Supervisor will also inspect to see if the items matches the one bought on the farmer and accept the items by Remarks. The accountant will check to see that every transaction matches up with the money money and the bank transfers. This means the accountant will be able to see all dad to day transaction. The Dashboard should display the total tons purchased so and amount spent on daily, weekly, monthly and yearly basis. All transactions should be in real-time. In an event where there is no network, the application should be able to sync as soon as it gets network connection. It means the application should work both online and offline. The application should be flexible enough to add more features as it becomes necessary. It should also be highly secured as possible.